helos need ffb for simulating force trim; while since warbirds using cables/rods etc to connect flight controls and control surfaces, FFB is needed.
That said, modern planes, including some of the FBWers, FFB is still valuable for programming a more realistic curve and swapping btwn different type of aircrafts with ease, as well as for simulating the trim actuator that move the stick when trimming, and Autopilot actuator for some.